Scan Tool Data Definitions

Scan Tool Data Definitions

This information will assist in emission or driveability problems. The displays can be viewed while the vehicle is being driven. Always perform the Diagnostic System Check - SCR Controls first. The Diagnostic System Check will confirm proper system operation.

Accelerator Pedal Position (APP) Indicated Angle

This parameter displays the angle of the accelerator pedal as calculated by the ECM using the signals from the accelerator pedal position (APP) sensors. The scan tool will display linearly from 0 to 100% according to the pedal operation.

Barometric Pressure

This parameter displays the barometric pressure (BARO) as calculated by the ECM using the signal from the BARO sensor. The scan tool will display a low barometric pressure in high altitude area.

DEF (Diesel Exhaust Fluid) Supply Pump Temperature

This parameter displays the temperature of the DEF in the DEF supply pump as calculated by the DCU using the signal from the DEF supply pump temperature sensor.

Desired Fuel Injection Quantity

This parameter displays fuel injection quantity in L/hr based on input to the ECM from various engine sensors.

Diesel Exhaust Fluid (DEF) Reverting Valve

This parameter displays the commanded state of the DEF reverting valve control circuit. ON indicates the valve is switched to return side by the DCU.

Diesel Exhaust Fluid (DEF) Supply Pressure

This parameter displays the DEF pressure as calculated by the DCU using the signal from the DEF supply pressure sensor.

Diesel Exhaust Fluid (DEF) Supply Pump Motor Control Duty Ratio

This parameter displays the DEF supply pump motor control duty ratio based on outputs to the DEF supply pump from DCU. The scan tool will display a higher percentage when the pump is controlled at high speed.

Diesel Exhaust Fluid (DEF) Tank Heater Coolant Control Valve

This parameter displays the commanded state of the DEF tank heater coolant control valve control circuit. ON indicates the valve is opened.

Diesel Exhaust Fluid (DEF) Tank Level

This parameter displays the DEF level in the DEF tank as calculated by the DCU using the signal from the DEF level sensor. The scan tool will display from 18% to 99% depending upon the DEF level.

Diesel Exhaust Fluid (DEF) Tank Temperature

This parameter displays the temperature of the DEF in the DEF tank as calculated by the DCU using the signal from the DEF tank temperature sensor. The scan tool will display a low temperature when the signal voltage is high, and a high temperature when the signal voltage is low.

Engine Coolant Temperature (ECT)

This parameter displays the temperature of the engine coolant as calculated by the ECM using the signal from the engine coolant temperature (ECT) sensor. The scan tool will display a low temperature when the signal voltage is high, and a high temperature when the signal voltage is low.

Engine Load

This parameter displays the engine load in percent based on inputs to the ECM from various engine sensors. The scan tool will display a lower percentage when the engine is at idle with little or no load. The scan tool will display a higher percentage when the engine is running at high engine speed under a heavy load.

Engine Speed

This parameter displays the rotational speed of the crankshaft as calculated by the ECM based on inputs from the crankshaft position sensor or camshaft position sensor.

Exhaust Gas Flow Amount

This parameter displays exhaust gas flow amount g/h based on input to the ECM from various engine sensors.

Exhaust Gas Recirculation (EGR) Ratio

This parameter displays EGR valve position in percent based on input to the ECM from EGR position sensor. The scan tool will display a lower percentage when the valve is controlled to close (EGR gas supply to the intake is reduced). The scan tool will display a higher percentage when the valve is controlled to open (EGR gas supply to the intake is increased).

Exhaust Gas Temperature (EGT) 1

This parameter displays the temperature of the exhaust gas in front of oxidation converter as calculated by the ECM using the signal from the exhaust gas temperature (EGT) sensor 1. The scan tool will display a low temperature when the signal voltage is high, and a high temperature when the signal voltage is low.

Exhaust Gas Temperature (EGT) 2

This parameter displays the temperature of the exhaust gas in front of diesel particulate filter as calculated by the ECM using the signal from the exhaust gas temperature (EGT) sensor 2. The scan tool will display a low temperature when the signal voltage is high, and a high temperature when the signal voltage is low.

Exhaust Gas Temperature (EGT) 3

This parameter displays the temperature of the exhaust gas in front of SCR converter as calculated by the DEF Control Module using the signal from the exhaust gas temperature (EGT) sensor 3. The scan tool will display a high temperature when the signal voltage is high, and a low temperature when the signal voltage is low.

Intake Air Temperature (IAT) 1

This parameter displays the temperature of the intake air as calculated by the ECM using the signal from the intake air temperature (IAT) sensor 1. The scan tool will display a low temperature when the signal voltage is high, and a high temperature when the signal voltage is low.

NOx Concentration Upstream

This parameter displays the NOx concentration in the SCR catalyst upstream as calculated by the DCU using the signal from the NOx sensor 1. The scan tool will display from 0 ppm to 3,012 ppm depending upon the NOx concentration.

NOx Sensor 1 Heater Circuit Error

This parameter displays an error state of the heater circuit of NOx sensor 1 that the DCU received from the NOx sensor 1. The scan tool will display Short Circuit when the circuit is short, and Open Circuit when the circuit is open.

NOx Sensor 1 Heater Control Status

This parameter displays the control state of the NOx sensor 1 heater that the DCU received from the NOx sensor 1.

NOx Sensor 1 NOx Detection

This parameter displays the operation state of the NOx sensor 1 that the DCU received from the NOx sensor 1. The scan tool will display Invalid when the sensor is not measuring, and Valid when the sensor is measuring.

NOx Sensor 1 NOx Detection Circuit Error

This parameter displays an error state of the NOx detection circuit of NOx sensor 1 that the DCU received from the NOx sensor 1. The scan tool will display Short Circuit when the circuit is short, and Open Circuit when the circuit is open.

NOx Sensor 1 O2 Detection Circuit Error

This parameter displays an error state of the O2 detection circuit of NOx sensor 1 that the DCU received from the NOx sensor 1. The scan tool will display Short Circuit when the circuit is short, and Open Circuit when the circuit is open.

NOx Sensor 2 Heater Error Status

This parameter displays an error state of the heater circuit of NOx sensor 2 that the DCU received from the NOx sensor 2. The scan tool will display Short Circuit when the circuit is short, and Open Circuit when the circuit is open.

NOx Sensor 2 NOx Detection

This parameter displays the operation state of the NOx sensor 2 that the DCU received from the NOx sensor 2. The scan tool will display Invalid when the sensor is not measuring, and Valid when the sensor is measuring.

NOx Sensor 2 NOx Detection Circuit Error

This parameter displays an error state of the NOx detection circuit of NOx sensor 2 that the DCU received from the NOx sensor 2. The scan tool will display Short Circuit when the circuit is short, and Open Circuit when the circuit is open.

NOx Sensor 2 O2 Detection Circuit Error

This parameter displays an error state of the O2 detection circuit of NOx sensor 2 that the DCU received from the NOx sensor 2. The scan tool will display Short Circuit when the circuit is short, and Open Circuit when the circuit is open.

PTO Status

This parameter displays the input state of the remote PTO resume switch to the ECM. When the PTO switch is pressed or the PTO remote throttle is operated, the scan tool displays ON.

SCR System Control Status 1

This parameter displays the status of DEF pressure control in the SCR system.

SCR System Control Status 2

This parameter displays the detailed control status of SCR System Control Status 1.

Turbocharger Boost Pressure

This parameter displays the boost pressure in the intake duct as calculated by the ECM using the signal from the boost pressure sensor. The scan tool will display a low pressure when the low engine load, and a high pressure when the high engine load. Note that the true boost pressure is determined by subtracting barometric pressure from the actual reading.

Vehicle Speed

This parameter indicates the vehicle speed calculated by the ECM using the signal from the vehicle speed sensor (VSS) 2. The scan tool will display a low value at lower vehicle speeds, and a high value at higher vehicle speeds.